Electronic control unit

Abstract

An electronic control unit installed on a high temperature heat source or in its vicinity exhibits an improved heat dissipation ability within its installation environment. The electronic control unit has a chassis incorporating a printed circuit board where electronic devices are mounted. The outer surface of the chassis on the side of the high temperature heat source has a coating for lowering infrared absorption, while the outer surface of the chassis on the side away from the high temperature heat source has a coating for enhancing heat emissivity. Preferably, the inner surfaces of the chassis are subject to a surface treatment for increasing infrared absorption.

1. An electronic control unit to be installed proximate to a high temperature heat source, the electronic control unit comprising:
 a chassis incorporating a circuit board where electronic devices are mounted, wherein  
 an outer surface of said chassis to be installed on a side facing said high temperature heat source has a lower heat absorption/emissivity coefficient than the outer surface of said chassis to be installed on a side facing away from said high temperature heat source.  
 
   
   
     2. The electronic control unit as in  claim 1 , wherein said high temperature heat source is an internal combustion engine providing a thermal load that changes with operating conditions. 
   
   
     3. The electronic control unit as in  claim 1 , wherein one of said outer surfaces of the chassis is an untreated surface of the material forming said chassis and the other outer surface incorporates a predetermined surface treatment. 
   
   
     4. The electronic control unit as in  claim 2 , wherein one of said outer surfaces of the chassis is an untreated surface of the material forming said chassis and the other outer surface incorporates a predetermined surface treatment. 
   
   
     5. The electronic control unit as in  claim 1 , wherein both said outer surfaces of said chassis incorporate surface treatments but differing from each other. 
   
   
     6. The electronic control unit as in  claim 2 , wherein both said outer surfaces of said chassis incorporate surface treatments but differing from each other. 
   
   
     7. The electronic control unit as in  claim 1 , wherein an inner cavity surface of said chassis incorporates a surface treatment for increasing its infrared absorption coefficient. 
   
   
     8. The electronic control unit as in  claim 2 , wherein an inner cavity surface of said chassis incorporates a surface treatment for increasing its infrared absorption coefficient. 
   
   
     9. The electronic control unit as in  claim 3 , wherein an inner cavity surface of said chassis incorporates a surface treatment for increasing its infrared absorption coefficient. 
   
   
     10. The electronic control unit as in  claim 4 , wherein an inner cavity surface of said chassis incorporates a surface treatment for increasing its infrared absorption coefficient. 
   
   
     11. The electronic control unit as in  claim 5 , wherein an inner cavity surface of said chassis incorporates a surface treatment for increasing its infrared absorption coefficient. 
   
   
     12. The electronic control unit as in  claim 6 , wherein an inner cavity surface of said chassis incorporates a surface treatment for increasing its infrared absorption coefficient. 
   
   
     13. The electronic control unit as in  claim 1 , wherein:
 on each of a plurality of chassis surfaces on a chassis side component including said outer surface to be installed facing said high temperature heat source, an area in surface contact with another component incorporates a surface treatment for decreasing heat conduction, and  
 on each of a plurality of chassis surfaces on a chassis side component including said outer surface to be installed facing away from said high temperature heat source, an area in surface contact with another component incorporates a surface treatment for increasing heat conduction.  
 
   
   
     14. The electronic control unit as in  claim 6 , wherein:
 on each of a plurality of chassis surfaces on a chassis side component including said outer surface to be installed facing said high temperature heat source, an area in surface contact with another component incorporates a surface treatment for decreasing heat conduction, and  
 on each of a plurality of chassis surfaces on a chassis side component including said outer surface to be installed facing away from said high temperature heat source, an area in surface contact with another component incorporates a surface treatment for increasing heat conduction.  
 
   
   
     15. The electronic control unit as in  claim 12 , wherein:
 on each of a plurality of chassis surfaces on a chassis side component including said outer surface to be installed facing said high temperature heat source, an area in surface contact with another component incorporates a surface treatment for decreasing heat conduction, and  
 on each of a plurality of chassis surfaces on a chassis side, component including said outer surface to be installed facing away from said high temperature heat source, an area in surface contact with another component incorporates a surface treatment for increasing heat conduction.  
 
   
   
     16. The electronic control unit as in  claim 1 , wherein said chassis comprises a first housing unit holding said circuit board and a second housing unit, incorporating said circuit board, in combination with said first housing unit. 
   
   
     17. The electronic control unit as in  claim 15 , wherein said chassis comprises a first housing unit, holding said circuit board, and a second housing unit, incorporating said circuit board in combination with said first housing unit. 
   
   
     18. An electronic control unit for controlling an engine, the electronic control unit comprising:
 a circuit board on which is mounted at least one electronic component including a heat generating element;  
 a cover made of a metallic material that supports the circuit board; and  
 a metallic case that contains the circuit board together with the covering,  
 the cover and the case forming a chassis having an inner cavity surface incorporating a high infrared absorption coefficient treatment,  
 a heat conductive material disposed to transfer heat from the electronic component mounted on the circuit board to the chassis, and  
 a contacting point between the heat conductive material and the chassis being processed to have a relatively higher heat conductivity than other portions of the chassis.  
 
   
   
     19. A method for improved cooling of electronic control unit components located in a chassis housing that is to be mounted proximate a high temperature heat source, said method comprising:
 surface treating at least one outer surface of the chassis housing so as to cause a first side to be mounted most proximate the heat source to have a lower heat absorption/emissivity coefficient than a second other side of the chassis housing.  
 
   
   
     20. A method as in  claim 19  wherein said surface treatment is effected on said second other side. 
   
   
     21. A method as in  claim 19  wherein said first and second sides are each subjected to predetermined but differing surface treatments. 
   
   
     22. A method as in  claim 19  wherein said chassis housing has at least one internal cavity surface incorporating surface treatment for increasing its infrared absorption coefficient. 
   
   
     23. A method as in  claim 19  wherein said chassis housing comprises plural components fastened together at first joint areas and wherein at least one of said components is adapted to be fastened to said high temperature heat source at second joint areas, said method further comprising:
 surface treating at least one of said first joint areas so as to increase its heat conduction coefficient; and  
 surface treating at least one of said second joint areas to decrease its heat conduction coefficient.